7-285 Donadeo Innovation Centre for Engineering, Environmental Engineering Program, Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
Environ Sci Process Impacts. 2017 Jan 25;19(1):31-37. doi: 10.1039/c6em00501b.
Photoreactivation is a process where ultraviolet (UV)-induced damage to the DNA of microorganisms can be reversed by exposure to near UV and visible light. To date, most photoreactivation experiments have been carried out under laboratory conditions using standard microorganisms that do not reflect the natural conditions of municipal wastewater effluents. Photoreactivation could increase the concentration of pathogens released into natural systems, leading to negative impacts on fish, shellfish, and clams. In addition, pathogen release can increase health risks of downstream activities, such as swimming. This study focused on the photoreactivation of total coliforms in municipal wastewater effluents under natural sunlight conditions. The concept of 'effective reactivation fluence' (ERF) is used to evaluate and normalize the results from various light sources for a direct comparison. ERF values higher than 30 J cm, in conjunction with lowered nutrient concentrations (dilution of effluents with river water), decreased the photoreactivation of total coliforms. In contrast, higher temperatures (up to 25 °C) and blocking the UV-B portion of natural sunlight using a polyethylene terephthalate (PET) bottle increased their photoreactivation. The results of this research will provide guidance to wastewater plant operators on the potential need to minimize the level of photoreactivation in effluents before the effluents were released into receiving water bodies.
光复活是一种过程，其中微生物的 DNA 中由紫外线（UV）引起的损伤可以通过暴露于近 UV 和可见光来逆转。迄今为止，大多数光复活实验都是在使用标准微生物的实验室条件下进行的，这些标准微生物不能反映城市废水的自然条件。光复活可能会增加释放到自然系统中的病原体的浓度，从而对鱼类、贝类和贻贝产生负面影响。此外，病原体的释放会增加下游活动（如游泳）的健康风险。本研究重点研究了在自然阳光条件下城市废水废水中总大肠菌群的光复活。“有效再激活通量”（ERF）的概念用于评估和归一化各种光源的结果，以便直接比较。大于 30 J cm 的 ERF 值，结合降低的营养物浓度（用河水稀释废水），降低了总大肠菌群的光复活。相比之下，较高的温度（高达 25°C）和使用聚对苯二甲酸乙二醇酯（PET）瓶阻挡自然光中的 UV-B 部分增加了它们的光复活。本研究的结果将为废水处理厂操作人员提供指导，即在将废水排入受纳水体之前，需要尽量减少废水中的光复活水平。
